Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Chemistry (Inorganic) > Group 7 > Flashcards

Group 7 Flashcards

1
Q

Describe the trend in reducing abilities of halide ions

A

Reducing ability increases down the group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Explain the trend in reducing abilities of halide ions

A

Reducing ability increases down the group
- Ionic size increases down the group
- Shielding increases
- Attraction between outer electron and nucleus decreases
- So electron is more easily lost

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the type of reaction between halide and concentrated H2SO4

A

Acid base reaction (and redox after Cl- and F-)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the observation when Br2 is formed

A

Brown/orange fumes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the observation when I2 is formed

A

Black solid/ Purple fumes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the observation when SO2 is formed

A

Pungent gas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the observation when S is formed

A

Yellow solid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the observation when H2S is formed

A

Smell of bad eggs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the trend in electronegativity of halides

A

Decreases down the group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Explain the trend in electronegativity of halides

A

Decreases down the group

  • Atomic size increases
  • Shielding increases
    -Weaker attraction between nucleus and shared pair of e- of the covalent bond
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

State the trend in boiling point of the halides

A

Boiling point increases down the group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Explain the trend in boiling point of the halides

A

Boiling point increases down the group

  • Molecular size increases
  • Number of electrons increases
  • Van der waals forces between molecules increases
  • More energy required to overcome these forces
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the best oxidising agent out of the halides

A

F2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the worst oxidising agent out of the halides

A

I2 (more shielding therefore worse at gaining an electron)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the best reducing agent out of the halide ions

A

I-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the worst reducing agent out of the halides

A

F-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is observed when Cl2 is formed?

A

Green solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the 4 steps in testing for halide ions

A

1) Add HNO3
2) Add AgNO3
3) Add dilute NH3
4) Add concentrated NH3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Why do we add HNO3 (nitric acid) in the first step of identifying halide ions (why is silver nitrate acidified)
Write an equation for this reaction

A

Removes Co32- ions
(essential as Ag2CO3 is a white ppt)

2 HNO3 + Na2CO3 —> 2 NaNO3 + H2O + CO2

(Na is from compound like NaBr)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Which element is clearly identified after adding AgNO3 in the halide ion test

A

F-
(Gives a colourless solution)
(The others give white, cream and yellow)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Which element is clearly identified after adding DILUTE NH3 in the halide ion test. Write the equation for this reaction

A

Cl-
(In Cl- white ppt dissolves, Br- and I- have no visible change)

AgCl(s) + 2NH3(aq) —> [Ag(NH3)2]+(aq) + Cl- (aq)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Which element is clearly identified after adding CONCENTRATED NH3 in the halide ion test. Write the equation for this reaction

A

Br-
(In Br- cream ppt dissolves, I- has no visible change)

AgBr(s) + 2NH3(aq) —> [Ag(NH3)2]+ (aq) + Br - (aq)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the test for I- ions

A

No visible change after completing all 4 steps of halide ion test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the formula for the chlorate ion

A

ClO-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is the equation for the reaction of chlorine and water without UV light, what type of reaction is this
Cl2 + H2O -->HCl + HClO (reversible) Ionic: Cl2 + H2O --> 2H+ + Cl- + ClO- (Reversible) Disproportionation reaction (Cl2 both oxidised and reduced)
26
What is a disproportionation reaction?
One where the same species is both oxidised and reduced simultaneously
27
Why is the reaction of chlorine and water without UV a disproportionation reaction
Cl2 is both oxidised and reduced
28
Which species is oxidised and which species is reduced in the reaction of chlorine and water without UV
Cl2 is reduced and oxidised
29
What is the benefit of adding Cl2 to water
Cl2 kills microorganisms (useful in pools and drinking water)
30
What is the risk of adding cl2 to water
Cl is toxic to humans in large amounts
31
What is the equation for the reaction of Cl and water with UV (sunlight)
2Cl2 + 2H2O ---> 4HCl + O2 Ionic: 2Cl2 + 2H2O ---> 4H+ + 4Cl- + O2 (Green colour of Cl2 slowly fades as it reacts)
32
Which species is oxidised and which species is reduced in the reaction of chlorine and water with UV
2Cl2 is Reduced 2H2O is Oxidised
33
What is the chemical formula for bleach
Sodium Chlorate(I) NaClO
34
What is the equation for the manufacture of bleach What is the colour change for this reaction
Cl2 + 2NaOH --> NaCl + NaClO + H2O Ionic: Cl2 + 2OH- ---> Cl- + ClO- + H2O Pale green to colourless
35
Which species is oxidised and which is reduced in the reaction for the manufacture of bleach
Cl2 is oxidised and reduced
36
What type of reaction is the manufacture of bleach
Disproportionation
37
State the colours of precipitate formed when AgNO3 is added to Cl-,Br-, and I- Write the ionic equation for each
Chloride (Cl-) ions: Produce a white precipitate of silver chloride Ag+(aq) + Cl-(aq) --> AgCl(s) Bromide (Br-) ions: Produce a cream precipitate of silver bromide Ag+(aq) + Br-(aq) --> AgBr(s) Iodide (I-) ions: Produce a yellow precipitate of silver iodide Ag+(aq) + I-(aq) --> AgI(s)
38
What colour is F2, state a property of it
Very pale yellow gas Highly reactive
39
What colour is Cl2, state a property of it
Greenish, reactive gas, poisonous in high concentrations
40
What colour is Br2, state a property of it
Brown-Orange liquid, gives off dense brown/orange poisonous fumes
41
What colour is I2, state a property of it
Shiny grey solid, sublimes to purple gas
42
What do more reactive halogens displace
Less reactive halide ions in a compound
43
What is the trend in reactivity of G7 HALIDES
Reactivity increases up the group For atoms reactivity increases down the group This is because halogen atoms are oxidising agents, and halide ions are reducing agents (e.g. they can reduce H2SO4)
44
What is the trend in oxidising ability of the halogens
Decreases down the group
45
What is observed when a solution of KCl is added to a solution of chlorine
Very pale green solution, no reaction
46
What is observed when a solution of KCl is added to a solution of bromine
Yellow-orange solution, no reaction
47
What is observed when a solution of KCl is added to a solution of iodine
Brown solution, no reaction
48
What colour is a test tube with chlorine present in solution
Very pale green solution (often colourless)
49
What colour is a test tube with bromine present in solution
Yellow - orange solution
50
What colour is a test tube with iodine present in solution
Brown solution (sometimes black solid present)
51
What is observed when a solution of KBr is added to a solution of chlorine Write the ionic equation for this reaction
Yellow-orange solution, Cl has displaced Br Cl2(aq) + 2Br –(aq) --> 2Cl –(aq) + Br2(aq) (NOT BROWN COS THATS I2)
52
What is observed when a solution of KBr is added to a solution of bromine
Yellow-orange solution, no reaction
53
What is observed when a solution of KBr is added to a solution of iodine
Brown solution, no reaction
54
What is observed when a solution of KI is added to a solution of chlorine Write the ionic equation for this reaction
Brown solution, Cl has displaced I Cl2(aq) + 2I–(aq) --> 2Cl –(aq) + I2(aq)
55
What is observed when a solution of KI is added to a solution of bromine Write the ionic equation for this reaction
Brown Solution, Br has displaced I Br2(aq) + 2I–(aq) ---> 2Br–(aq) + I2(aq)
56
What is observed when a solution of KI is added to a solution of iodine
Brown Solution, no reaction
57
What does the colour of a test tube after a halogen displacement reaction tell us
The colour of the solution in the test tube shows which free halogen is present in solution. (NOT HALIDE ION) Chlorine =very pale green solution (often colourless), Bromine = yellow-orange solution Iodine = brown solution (sometimes black solid present)
58
How do we make bleach
Reaction of chlorine with cold, dilute, aqueous NaOH
59
Why does the Cl2 we add to swimming pools have to be replaced regularly
Sunlight can decompose chlorinated water, yet no ClO- is made which is what kills bacteria
60
What are some uses of bleach
Cleaning products Treating water
61
Which out of these is an oxidising agent and which is a reducing agent: Halogen and halide ion
Halogen - Oxidising agent Halide ion - reducing agent
62
Sketch the sable showing the products of the reaction between concentrated H2SO4 and Cl-, Br- and I-
NaF is the same as Cl
63
What is the product with the lowest oxidation state of S that H2SO4 can be reduced to when reacting with Cl- (furthest product it can be oxidised to)
HSO4-
64
What is the product with the lowest oxidation state of S that H2SO4 can be reduced to when reacting with Br- (furthest product it can be oxidised to)
SO2
65
What is the product with the lowest oxidation state of S that H2SO4 can be reduced to when reacting with I- (furthest product it can be oxidised to)
H2S
66
What is the order of the possible products when halide ions react with concentrated H2SO4 in order from the highest oxidation state of S to the lowest
NaHSO4/HSO4- SO2 S H2S
67
What happens to halide ions when they react with concentrated H2SO4
They are oxidised to give a halogen
68
What is the observation when a hydrogen halide is produced (HF, HCl, HBr, HI)
White steamy fumes evolved
69
What do we get when we add add concentrated NH3 to any silver halide apart from AgI
Tollens Halide ion
70
71
Write equations and state the observations for the reaction of NaF and NaCl with H2SO4 State what type of reaction occurs
NaF(s) + H2SO4(l) ---> NaHSO4(s) + HF(g) White steamy fumes of HF are evolved. NaCl(s) + H2SO4(l) ----> NaHSO4(s) + HCl(g) Observations: White steamy fumes of HCl are evolved. F- and Cl- ions are not strong enough reducing agents to reduce the S in H2SO4. No redox reactions occur. Only acid-base reactions occur.
72
What is the role of H2SO4 when it reacts with NaF or NaCl
H2SO4 plays the role of an acid (proton donor).
73
Write equations and state the observations for the reaction of NaBr with H2SO4 State what type of reactions occur
Acid- base step: NaBr(s) + H2SO4(l) ---> NaHSO4(s) + HBr(g) White steamy fumes of HBr are evolved. Redox step: 2HBr + H2SO4 ---> Br2(g) + SO2(g) + 2H2O(l) Red fumes of Bromine are also evolved and a colourless, acidic gas SO2 H2SO4 plays the role of acid in the first step producing HBr and then acts as an oxidising agent in the second redox step.
74
Write the half equations for the reaction of NaBr with H2SO4
Ox ½ equation 2Br- ---> Br2 + 2e- Re ½ equation H2SO4 + 2 H+ + 2 e- ---> SO2 + 2H2O LEARN HALF EQUATIONS THEN CAN PUT TOGETHER FULL EQUATIONS IN EXAM
75
Write equations and state the observations for the reaction of NaI with H2SO4 State what type of reactions occur
NaI(s) + H2SO4(l) ---> NaHSO4(s) + HI(g) White steamy fumes of HI are evolved. 2HI + H2SO4 ---> I2(s) + SO2(g) + 2H2O(l) Black solid and purple fumes of Iodine are also evolved A colourless, acidic gas SO2 6HI + H2SO4 ---> 3I2 + S (s) + 4H2O (l) A yellow solid of Sulphur 8HI + H2SO4 ---> 4I2(s) + H2S(g) + 4H2O(l) H2S (Hydrogen Sulphide), a gas with a bad egg smell H2SO4 plays the role of acid in the first step producing HI and then acts as an oxidising agent in the three redox steps
76
Write the half equations for the reactions of NaI with H2SO4
(1) Ox ½ equation 2I - ---> I2 + 2e- Re ½ equation H2SO4 + 2 H+ + 2 e- ----> SO2 + 2H2O (2) Ox ½ equation 2I - ---> I2 + 2e- Re ½ equation H2SO4 + 6 H+ + 6 e- ----> S + 4H2O (3) Ox ½ equation 2I - ---> I2 + 2e- Re ½ equation H2SO4 + 8 H+ + 8 e- ----> H2S + 4H2O LEARN HALF EQUATIONS THEN CAN PUT TOGETHER FULL EQUATIONS IN EXAM
77
Write the half equation for the formation of Br2 from Br- State whether this is oxidation or reduction
Ox ½ equation 2Br- ---> Br2 + 2e-
78
Write the half equation for the formation of I2 from I- State whether this is oxidation or reduction
Ox ½ equation 2I - ---> I2 + 2e-
79
Write the half equation for the formation of SO2 from H2SO4 State whether this is oxidation or reduction
H2SO4 + 2 H+ + 2 e- ---> SO2 + 2H2O
80
Write the half equation for the formation of S from H2SO4 State whether this is oxidation or reduction
H2SO4 + 6 H+ + 6 e- ----> S + 4H2O
81
Write the half equation for the formation of H2S from H2SO4 State whether this is oxidation or reduction
H2SO4 + 8 H+ + 8 e- ----> H2S + 4H2O
82
What does the MS often put in the H2SO4 with halide redox equations
Instead of HI etc, they put H+ + I-
83
What is the equation to show how AgCl dissolves in dilute NH3
AgCl(s) + 2NH3(aq) → Ag(NH3)2+(aq) + Cl−(aq)
84
What is the equation to show how AgBr dissolves in excess dilute NH3
AgBr(s) + 2NH3(aq) → [Ag(NH3)2]+(aq) + Br−(aq)

Chemistry (Inorganic) (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions